Bleach containing compositions for bleaching fabrics and treating surfaces are well known in the art. Liquid peroxygen bleach containing compositions have been extensively described in the art, especially in laundry applications as laundry detergents, laundry additives or laundry pretreaters. The use of such peroxygen bleach containing compositions in laundry applications to boost the removal of encrusted stains and soils such as grease, coffee, tea, grass, mud/clay containing soils which are otherwise particularly difficult to remove by typical machine washing is known in the art.
Although the known liquid aqueous bleaching compositions provide some bleaching performance when used to treat a soiled fabric, there is room for further improvement regarding the stain removal performance on various stains including for example greasy stains as well as for further improvement in bleaching performance under various conditions such as pretreatment conditions where the liquid composition is applied neat on the fabric to bleach before the fabric is rinsed or washed then rinsed with water.
It is know that the stain removal performance of liquid aqueous peroxygen bleach containing compositions may be improved by the addition of a surfactant or a surfactant system. For example liquid bleaching compositions having a pH below 7, comprising a peroxygen bleach, a sulphonated anionic surfactant and a second surfactant selected from nonionic surfactants amphoteric surfactants, zwitterionic surfactants and mixtures thereof is disclosed in WO 00/27971.
However, there are some limitations to the convenience of such liquid bleaching compositions. In particular, the stain removal performance is not yet fully satisfactory for the consumer and the viscosity of such combinations is typically low such that thickener agents such as polymers are added to provide a gel like consistency.
It is there for an object of the present invention to provide a liquid bleaching composition whereby the composition shows good stain removal performance and a gel like viscosity without the addition of polymeric thickeners.
It has been found that the object can be efficiently met by a formulating a liquid bleaching composition comprising a peroxygen bleach and a sulphonated anionic surfactant and an amphoteric/zwitterionic surfactant where the ratio of amphoteric/zwitterionic surfactant to sulfonated anionic surfactant is greater than about 0.3. The liquid bleaching composition of the present invention exhibits a viscosity of up to 28,800 centipoise without the additional of any polymeric or other thickening agents. It was found that the specific surfactant combination of the present invention could provide both viscosity enhancement and increase stain removal performance.